Baseline predictors of response to treatment with darbepoetin-alpha (DA) in anemic patients with low-risk myelodysplastic syndrome (MDS)

Abstract

7081 Background: Patients (pts) with MDS often develop anemia, resulting in fatigue and an increased requirement for transfusions. The erythropoiesis-stimulating agent (ESA) DA can raise hemoglobin (Hb) levels in low-risk MDS pts. Previous analyses suggest that baseline (BL) endogenous erythropoietin (eEPO) levels and French-American-British (FAB) disease category are predictors of response to ESAs. Methods: This was a phase 2, open-label, 52-week (wk) study of DA administered 500 mcg every 3 wks (Q3W) to anemic (Hb=11g/dL), low- or intermediate-risk MDS pts. Pts received 500 mcg DA Q2W if they did not respond by wk 7. The last DA dose was at wk 52; end of study was wk 53 or 55 for pts receiving DA Q2W or Q3W, respectively. The primary endpoint was % pts with an erythroid response (International Working Group criteria) by wk 13. Other endpoints included change from BL in Hb and FACT-F score. Exploratory analyses examined the incidence of erythroid responses adjusted by FAB category (refractory anemia [RA], RA with ringed sideroblasts [RARS], or RA with excess blasts [RAEB]). Results: Final 53/55 wk data will be presented. Results were stratified by whether pts received an ESA before enrollment (ESA-naive [ESA-N] vs ESA-treated [ESA-T]). ESA-T pts are a heterogeneous group and their data are difficult to interpret; thus, predictors of response will be presented for ESA-N pts only. Of 144 ESA-N pts, 56% had RA, 37% had RARS, and 7% had RAEB. Most ESA-N pts achieved the target Hb and had a major erythroid response ( Table ). Pts with RA were more likely to achieve a major erythroid response than pts with RARS or RAEB. For ESA-T pts, demographics and type/length of ESA treatment will be presented. Of all pts, serious adverse events (SAEs) were reported in 62 (30%) pts and treatment-related SAEs in 2 (1%) pts. Conclusions: FAB category may affect response to DA in MDS pts. Additional data will be presented on the effect of BL eEPO, transfusion needs, and previous ESA treatment on response and duration of response. [Table: see text]